The present invention relates to computer systems. More particularly, the present invention relates to access to computer system components via an external multi-purpose interface.
In prior art computer systems, the processor typically cannot be accessed directly for diagnostic or other purposes when the computer system case is fully assembled. Because access to the processor is required for basic input/output system (BIOS) development, operating system (O/S) and O/S driver development, application-level source code debugging, code execution time analysis, manufacturing testing and system diagnostics, prior art computer systems require the case to be open during several phases of development, VALIDATION and repair, which may expose computer system components to damage from external conditions such as electrostatic discharge (ESD), physical damage, etc. Opening of the computer system case also makes diagnostics and testing more difficult than performing the same operations without opening the computer system case.
Prior art desktop computer system often include a diagnostic port on the computer system motherboard. The diagnostic port is typically located within a relatively short physical distance of the processor(s) and is used for BIOS development, O/S and O/S driver development, application-level source code debugging, code execution time analysis, manufacturing testing and repair testing. However, because mobile motherboards are more densely packed, the local diagnostic port is typically not provided, and if provided not exposed.
When a diagnostic port is desired an interposer board is placed between the mobile computer system processor and the mobile system motherboard. The interposer board includes the diagnostic port as well as support circuitry. However, use of interposer boards require that the processor be removed from the motherboard and installed on the interposer board. The interposer board is then coupled to the motherboard. This process exposes the processor and other system components to damage. Furthermore, interposer boards are not practical for use by an end consumer of the mobile computer system.
What is needed is a method and apparatus for accessing the processor of a computer system when the case of the computer system is fully assembled.
A method and apparatus for direct processor access via an external multi-purpose interface is described. The processor is coupled to the external multi-purpose interface by a bus. The external multi-purpose interface has a detection device that detects a diagnostic tool coupled to the interface. The interface is coupled directly to the processor in response to the diagnostic tool being coupled to the interface.